2003/07/28 by Yun‐Jie Xia, Yun-Jie Xia, Guang-Can Guo +1
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum and electron transport phenomena #quant-ph
paper · pdf · doi:10.1088/0256-307x/21/10/003
5 pages
arxiv created 2003/07/28 · openalex publication_date 2004/10/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
Based on total variance of a pair of Einstein–Podolsky–Rosen (EPR) type operators, the generalized EPR entangled states in continuous variable systems are defined. We show that such entangled states must correspond to two-mode squeezing states whether these states are Gaussian or not and whether they are pure or not. With help of the relation between the total variance and the entanglement, the degree of such entanglement is also defined. Through analysing some specific cases, we see that this method is very convenient and easy in practical applications. In addition, an entangled state with no squeezing is studied, which reveals that there certainly exists something unknown about entanglement in continuous variable systems.